One of the ways of the utilisation of chromium-free tannery wastes may be their processing into organic fertilisers. Two methods are taken into consideration: methane fermentation and composting. It has been found that alongside gas recovery, methane fermentation of chromium-free tannery wastes allows to obtain material that is dewatered in different degree, with various, but always high, content of fertilising components. The final properties are determined by the kind of wastes (proportions in which various wastes have been mixed), and by conditions of the process. The paper offers a preliminary fertilising characteristics of various sludges and sludge liquids. The results confirm that it is possible to obtain biologically stable fertilising products of big, or even very big, fertilising value from nasty chromium-free tannery wastes.

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